On Sun, 14 Feb 2016, Emilio López wrote: > From: Reilly Grant <reillyg@xxxxxxxxxxxx> > > The new USBDEVFS_DROP_PRIVILEGES ioctl allows a process to voluntarily > relinquish the ability to issue other ioctls that may interfere with > other processes and drivers that have claimed an interface on the > device. > > This commit also includes a simple utility to be able to test the > ioctl, located at Documentation/usb/usbdevfs-drop-permissions.c > > Example (with qemu-kvm's input device): > > $ lsusb > ... > Bus 001 Device 002: ID 0627:0001 Adomax Technology Co., Ltd > > $ usb-devices > ... > C: #Ifs= 1 Cfg#= 1 Atr=a0 MxPwr=100mA > I: If#= 0 Alt= 0 #EPs= 1 Cls=03(HID ) Sub=00 Prot=02 Driver=usbhid > > $ sudo ./usbdevfs-drop-permissions /dev/bus/usb/001/002 > OK: privileges dropped! > Available options: > [0] Exit now > [1] Reset device. Should fail if device is in use > [2] Claim 4 interfaces. Should succeed where not in use > [3] Narrow interface permission mask > Which option shall I run?: 1 > ERROR: USBDEVFS_RESET failed! (1 - Operation not permitted) > Which test shall I run next?: 2 > ERROR claiming if 0 (1 - Operation not permitted) > ERROR claiming if 1 (1 - Operation not permitted) > ERROR claiming if 2 (1 - Operation not permitted) > ERROR claiming if 3 (1 - Operation not permitted) > Which test shall I run next?: 0 > > After unbinding usbhid: > > $ usb-devices > ... > I: If#= 0 Alt= 0 #EPs= 1 Cls=03(HID ) Sub=00 Prot=02 Driver=(none) > > $ sudo ./usbdevfs-drop-permissions /dev/bus/usb/001/002 > ... > Which option shall I run?: 2 > OK: claimed if 0 > ERROR claiming if 1 (1 - Operation not permitted) > ERROR claiming if 2 (1 - Operation not permitted) > ERROR claiming if 3 (1 - Operation not permitted) > Which test shall I run next?: 1 > OK: USBDEVFS_RESET succeeded > Which test shall I run next?: 0 > > After unbinding usbhid and restricting the mask: > > $ sudo ./usbdevfs-drop-permissions /dev/bus/usb/001/002 > ... > Which option shall I run?: 3 > Insert new mask: 0 > OK: privileges dropped! > Which test shall I run next?: 2 > ERROR claiming if 0 (1 - Operation not permitted) > ERROR claiming if 1 (1 - Operation not permitted) > ERROR claiming if 2 (1 - Operation not permitted) > ERROR claiming if 3 (1 - Operation not permitted) > > Signed-off-by: Reilly Grant <reillyg@xxxxxxxxxxxx> > Signed-off-by: Emilio López <emilio.lopez@xxxxxxxxxxxxxxx> Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
